Karin S. Coyne, PhD, MPH, from Evidera in Bethesda, MD, and colleagues evaluated patients (62% female; 85% white) on opioid therapy for at least four weeks for chronic noncancer pain. OIC was assessed using an Internet-based survey at baseline (489 patients) and weeks 2, 4, 6, 8, 12, 16, 20, and 24. Sufficient laxative use (at least one laxative at least four times in past two weeks) and inadequate response (LIR; fewer than three bowel movements or at least one constipation symptom rated moderate or greater) defined 1xLIR, while 2xLIR was defined as sufficient laxative use of at least two laxatives from different drug classes and inadequate response.

The researchers found that at baseline, 27% of participants reported no laxative use, 25% had insufficient laxative use, and 48% had sufficient laxative use. Over the follow-up, 21–28% of patients had no or insufficient laxative use. At baseline, the prevalence of 1xLIR was 93%; it ranged from 59–81% across follow-up. For 2xLIR, 26% met criteria at baseline, while the range during follow-up was 11–20%.

"OIC among noncancer pain patients is a persistent and significant condition with varying utilization and response to laxatives thus increasing the ongoing burden of chronic pain," the authors write.

Three authors disclosed financial ties to AstraZeneca, which funded the study. Other authors disclosed ties to Evidera and United BioSource Corporation.